Over the past few years, considerable evidence has accumulated suggesting the existence of multiple rodent parvovirus strains that are distinct from Kilham's Rat Virus (KRV), Toolan's H-1 (H-1) and Minute Virus of Mice (MVM). These findings have raised great concern among the research community regarding the effect these newly-identified viruses may have on investigations utilizing infected laboratory animals, particularly in light of the fact that anomalous research findings have been associated with the use of animals infected with the well- characterized parvoviruses, MVM, H-1 and KRV. Because of the profound deleterious effects these viruses may have on biomedical research and because almost nothing is known about these viruses, further investigation of these agents is critically and immediately needed. The specific aims of this project include: 1) Molecular characterization of four newly-identified rodent parvovirus isolates and comparison of these isolates with well-characterized rodent parvoviruses. 2) Immunodiagnostic reagents will be developed by identifying and cloning gene sequences that code for conserved antigens shared among all rodent parvoviruses and unique, isolate-specific antigens. Recombinant gene products will be expressed in insect cells by a baculovirus expression system and used to develop genus- and species-specific enzyme-linked immunoassays. Once immunoassays are developed, the epidemiology of orphan parvovirus infections in laboratory animal populations will be assessed. In addition, a DNA amplification assay will be developed to identify cell cultures contaminated with rodent parvoviruses. Results of proposed studies will provide fundamental information about the biology of newly-identified parvoviruses that will be used to develop diagnostic reagents needed to identify and differentiate rodent parvovirus species. Availability of these reagents is critical to control of parvovirus infections in laboratory animals.